This invention relates to cabinets for storing and dispensing prescription medical items and medical and hospital supplies, which can be free standing, mounted on rollers, or built into a wall, for providing practitioners with access to the medications and other items. The invention is also concerned with a cabinet made of steel or other electrically conductive material, which may be radiopaque, and provided with a built-in RFID (Radio Frequency Identification) transducer for interrogating RFID-tagged inventory items within the cabinet, and reading the RFID responses from such items.
Many medical supply items, e.g., syringes, bandages and dressings, disinfectants, catheters, and patient medications, need to be available to health practitioners in the places where the patient is located. At the same time, it is important for the hospital supply technicians and pharmacy technicians to be aware of the inventory levels of items in the supply cabinets throughout the facility, so that they will be properly stocked, and when the items are needed they can be given without delay to the patient. In some cases, the identification of items within the cabinet, and the number of each such item can be discerned automatically, e.g., by reading RFID tags that are attached to the items or incorporated into the packaging of the item.
In most cases, steel cabinets are preferred because of their durability and reasonable price. However, where the cabinets and the shelves and compartments are formed of steel, the low-level RF signals used to interrogate the RFID tags do not penetrate into the compartments between shelves; and the low-level RF signals returned from RFID tags on the items in the cabinets do not pass out through the metal walls and shelves. When the cabinets are made of a non-metal, i.e., plastic or synthetic material, the RF signals can reach between the RF transducer or reader and the inventory items, but it is not possible to know what items are stored in which compartments. Moreover, in cabinet arrangements in which the RFID reader or transducer is located in a fixed location in or on a cabinet, the reflections of signals within the cabinet creates dead zones that make it difficult to capture returns from each and every one of the inventory items.
These cabinets may have electronic locking and unlocking features, to limit access only to authorized medical personnel, and incorporate software features giving them the capability of maintaining an audit trail of access.